The most common and most likely answer to this crossword clue is the 7 letter word ILLNESS
I
L
L
N
E
S
S
More clues leading to the result ILLNESS
- The Italian head accepting learner’s complaint
- Hush after street leaves complaint
- Complaint generated by lack of movement? No way!
- Saint renouncing silence? There’ll be a complaint!
- One litre fewer, round middle of evening — it makes me sick
- Bug over loch is evil
- A cold calm way to disappear?
- Breathes over large lens — turned cold?
- Complaint made by Imogen and head about pupils
- It could give one a bad head
Buddy explains!

The straight part
We know that "it makes me sick" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case it makes me sick = illness.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does ILLNESS mean?
ILLNESS noun- An instance of a disease or poor health.
- A state of bad health or disease.